Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

public class Two {

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskA solver = new TaskA();
        int t;
        //t = in.nextInt();
        t = 1;
        while (t > 0) {
            solver.call(in,out);
            t--;
        }
        out.close();
    }

    static class TaskA {
        public void call(InputReader in, PrintWriter out) {
            int n, m, a , b= 0 , c = 0;
            n = in.nextInt();
            m = in.nextInt();
            int[][] arr = new int[n][m];

            int[] row = new int[n];
            int[] column = new int[m];


            if(m>n) {

                for (int i = 0; i < n; i++) {
                    a = Integer.MAX_VALUE;
                    for (int j = 0; j < m; j++) {
                        arr[i][j] = in.nextInt();
                        a = Math.min(arr[i][j], a);
                    }

                    b += a;
                    row[i] = a;
                    for (int j = 0; j < m; j++) {
                        arr[i][j] -= a;
                    }
                }


                for (int i = 0; i < m; i++) {
                    a = Integer.MAX_VALUE;
                    for (int j = 0; j < n; j++) {
                        a = Math.min(arr[j][i], a);
                    }
                    c += a;
                    column[i] = a;

                    for (int j = 0; j < n; j++) {
                        arr[j][i] -= a;
                    }
                }
            }
            else{

                for (int i = 0; i < n; i++) {
                    for (int j = 0; j < m; j++) {
                        arr[i][j] = in.nextInt();
                    }
                }


                for (int i = 0; i < m; i++) {
                    a = Integer.MAX_VALUE;
                    for (int j = 0; j < n; j++) {
                        a = Math.min(arr[j][i], a);
                    }
                    c += a;
                    column[i] = a;

                    for (int j = 0; j < n; j++) {
                        arr[j][i] -= a;
                    }
                }

                for (int i = 0; i < n; i++) {
                    a = Integer.MAX_VALUE;
                    for (int j = 0; j < m; j++) {
                        a = Math.min(arr[i][j], a);
                    }

                    b += a;
                    row[i] = a;
                    for (int j = 0; j < m; j++) {
                        arr[i][j] -= a;
                    }
                }



            }

            a = 0;

            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    if(arr[i][j]!=0) {
                        a++;
                        break;
                    }
                }
            }

            if(a!=0){
                out.println(-1);
            }
            else{
                out.println(c+b);

                for (int i = 0; i < n; i++) {
                    if(row[i]==0)
                        continue;
                    for (int j = 0; j < row[i]; j++) {
                        out.println("row "+(i+1));
                    }

                }
                for (int i = 0; i < m; i++) {
                    if(column[i]==0)
                        continue;
                    for (int j = 0; j < column[i]; j++) {
                        out.println("col " + (i+1));
                    }
                }

            }



        }
    }


    static class answer implements Comparable<answer>{
        int a, b;

        public answer(int a, int b) {
            this.a = a;
            this.b = b;
        }


        @Override
        public int compareTo(answer o) {
            return this.a - o.a;
        }
    }


    static long lcm(long a , long b){
        return (a/gcd(a,b)) *b;
    }

    static long gcd(long a, long b)
    {
        if (b == 0)
            return a;
        return gcd(b,  a % b);
    }


    static final Random random=new Random();
    static void shuffleSort(int[] arr) {
        int n = arr.length;
        for (int i=0; i<n; i++) {

            int a=random.nextInt(n), temp=arr[a];
            arr[a]=arr[i];
            arr[i]=temp;

        }

        Arrays.sort(arr);

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }
        public long nextLong(){
            return Long.parseLong(next());
        }

    }
}